Class RolapProfilingEvaluator

Evaluator that collects profiling information as it evaluates expressions.

TODO: Cleanup tasks as part of explain/profiling project:

1. Obsolete AbstractCalc.calcs member, AbstractCalc.getCalcs(), and
Calc[] constructor parameter to many Calc subclasses. Store the
tree structure (children of a calc, parent of a calc) in
RolapEvaluatorRoot.compiledExps.

Rationale: Children calcs are
used in about 50 places, but mostly for dependency-checking (e.g.
AbstractCalc.anyDepends(mondrian.calc.Calc[], mondrian.olap.Hierarchy)). A few places uses
the calcs array but should use more strongly typed members. e.g.
FilterFunDef.MutableMemberIterCalc should have data members
'MemberListCalc listCalc' and 'BooleanCalc conditionCalc'.

2. Split Query into parse tree, plan, statement. Fits better into the
createStatement - prepare - execute JDBC lifecycle. Currently Query has
aspects of all of these, and some other state is held in RolapResult
(computed in the constructor, unfortunately) and RolapEvaluatorRoot.
This cleanup may not be essential for the explain/profiling task but
should happen soon afterwards.